Process to compact fabric



y 1968 T. A. DAVIS ET AL 3,382,552

PROCESS TO COMPACT FABRIC Filed March 24, 1965 2 Sheets-Sheet 1INVENTORS A. DAVIS D. GUTIERREZ ATTORNEY May 14, 1968 T. A. DAVIS ET AL.

PROCESS T0 COMPACT FABRIC 2 Sheets-Sheet 2 Filed March 24, 1965 FIG. "3

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THOMAS A. DAVIS CARLO S D. GUTIERREZ United States Patent 3,382,552PRGCESS T0 CQMPACT FABRIC Thomas A. Davis, Columbia, and Carlos D.Gutierrez,

Spartanhurg, S.C., assignors to Deering Millikan Research Corporation,Spartanburg, S.(,., a corporation of Delaware Filed Mar. 24, 1965, Ser.No. 442,291 8 Claims. (Cl. 26-13.6)

This invention relates to apparatus for the preparation of stretchfabric and more specifically to apparatus suitable for the preparationof stretch fabric having elastic characteristics in the direction of thefill yarns.

In general, elastic effects are produced in a fabric either by preparingfabrics from elastic yarns or by compacting preformed fabrics preparedfrom yarns having no prior stretch characteristics. Stretch yarns arecommonly prepared by employing an elastomeric component as a core aboutwhich non-elastic fibers are spun. A second means for producing stretchyarns is by compacting or crimping the yarns or the staple fibersemployed in the preparation of the yarns. Methods which are commonlyemployed for the preparation of such non-core spun stretch yarns aregear crimping, knit-unknit methods, edge-crimping, belt crimping,blowing methods and twistset-untwist methods.

While stretch fabrics may be prepared from the stretch yarns producedaccording to any of the aforementioned processes, great care must beexercised in the preparation of the stretch fabrics to insure that theelastic characteristics of the yarns are not lost in the subsequentknitting or weaving operations. It is therefore often desirable toproduce stretch characteristics in preformed fabrics. Stretch fabricsproduced in the piece are now being prepared according to US. PatentsNos. 3,077,655, 2,765,513, and 2,765,514. The first of these patentedprocesses involve a combination of factors among which are fabricconstruction, chemical treatments and mechanical action. In its mostgeneral terms, the process set forth in US. Patent No. 3,077,655involves the preparation of a loosely constructed fabric from high twistwool yarns, immersion of the fabric in a reducing agent followed byagitation of the fabric between vibrating members whereby the fabric isalternately compacted and released thereby permitting the high twistyarns to contract and create a stretch fabric having elasticcharacteristics in both the warp and fill direction. Another process forthe preparation of stretch fabric is embodied in US. Patents Nos.2,765,513 and 2,765,514. The process set forth in these two patentsinvolve the compacting of a fabric in the direction of the warp yarns bythe passage of the fabric into a machine consisting of two rolls and ablade. The b ade is in close proximity to the upper roll to form aprimary feed nip. A fabric entering the apparatus between the blade anda smooth compounded upper roll assumes the speed of that roll. Thefabric then passes from this primary nip to a second nip formed by thetwo rolls themselves. The lower roll possessing a higher coefficient offriction than the top roll and traveling at a slower speed than the toproll takes control of the fabric from the top roll because the fabric isbeing fed into the apparatus at a faster rate by the first nip and isbeing taken away at a slower rate. At the second nip the column offabric supported between the nip is under a state of longitudinalcompression and a fabric having elastic characteristics in the directionof the Warp yarns is created.

Stretched fabric developed in the piece according to the methodsheretofore known have resulted in a product having a certain degree ofstretch. It is found that, in general, these fabrics are limited to lessthan 25% extensibility in either the warp direction or the filldirection.

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The reason for this low degree of stretch is due to the fact thatcompacting in the direction of the warp yarns of a preformed fabric islimited by the high twist construction of the warp yarns in most fabricsand by the warp yarn tensions during weaving operations, both these hightwist and high tension characteristics tending to limit the degree towhich a fabric may be compacted in the direction of the warp yarns. Whena fabric is compacted by relying upon the internal contractions inherentin high twist years by subjecting a preformed fabric prepared from hightwist yarns to agitation, the yarns themselves will provide a limitingfactor to the degree of compaction which may be obtained. A secondlimiting factor to the degree of stretch obtainable from internal yarncontractions is that the agitated fabric held in an untensioned statewill buckle badly if extensive contraction is induced within the yarns.

it is therefore an object of this invention to provide an apparatuswhich will produce fabric that has stretch characteristics in the fillyarn direction.

It is another object of this invention to provide an apparatus for thepreparation of a fabric having stretch characteristics in the directionof the fill yarns by application of external forces in the direction ofthe fill yarns.

It is a further object of this invention to provide a continuous processfor the preparation of a fabric having stretch characteristics in thedirection of the fill yarns by application of external forces in thedirection of the fill yarns.

It is still another object of this invention to provide a fabric havingstretch characteristics in the direction of the fill yarns.

In accordance with this invention, it has now been discovered that it ispossible to produce a fabric having stretch characteristics along thedirection of the fill yarns by means of an apparatus comprising aplurality of stiff, rotatable, longitudinally curved shafts in parallelalignment, each of said shafts being in contact with at least one otherof said shafts and being in substantially the same plane. The curvedshaft members may be commercially available compactor rolls. Thecompactor roll with which this invention is concerned comprises a curvedshaft clamped at its ends, a series of metal roll sections rotatablymounted on the shaft in end-to-end relation by means of bearings and arubber-like sheath closely surrounding the roll sections and forming theworking surface of the roll. Rolls of this type are described in US.Patents Nos. 2,898,662 and 2,960,749 and are produced by the Mount HopeMachinery Company of Taunton, Mass.

If a sheet material is fed to the roll at its convex side and leaves theroll at its concave side, the sheet will tend to contract widthwise asit travels partly around the roll. As each of the plurality of rollmembers are in intimate contact with each other, the sheet material willretain that degree of compaction produced by one roll member when beingpassed to a succeeding roll member for further compaction. While anynumber of rolls in excess of two may be employed in the apparatus ofthis invention, the actual number is determined by the amount of totalcompacting desired and by the degree of compacting effected by each'adivi-dual roll member. It is preferred that the rolls have an outsidediameter of from about 1 inch to about 6.5 inches and have a radius ofcurvature or how sufficient to produce a compaction of from about 1% toabout 10%. It is also preferred that the bow of each successive rollincrease, in order to prevent wrinkling of the fabric during compactingoperations, that is to say the roll at the point of fabric ingressshould have the least amount of bow in the roll series while the roll atthe point of fabric egress should have the greatest amount of how in theroll series. If the compactor roll members are to be subjected to hightemperatures it is also desirable that the roll cover or sheath be madeof a heat resistant material such as silicone rubber or more preferablya fluorocarbon rubber such as, for instance, Viton (fluorocarbonelastomer marketed by E. I. du Pont de Nemours and Co.).

A better understanding of the invention may be had from the drawings inwhich:

FIGURE 1 is a schematic view of one embodiment of the apparatus of thisinvention.

FIGURE 2 is an expanded view of one portion of the apparatus of FIGURE1.

FIGURE 3 is an enlarged photograph of a polyester/ worsted fabric priorto compacting by means of external forces.

FIGURE 4 is an enlarged photograph of a polyester/ worsted fabricsubsequent to compacting by means of external forces.

FIGURE 5 is an enlarged (twenty power) cross-sectional photograph of thefabric of FIGURE 3.

FIGURE 6 is an enlarged (twenty power) cross-sectional photograph of thefabric of FIGURE 4.

FIGURE 7 is an enlarged (fifty power) cross-sectional photograph of acotton fabric prior to compacting.

FIGURE 8 is an enlarged (fifty power) cross-sectional photograph of acotton fabric subsequent to compacting by means of external forces.

FIGURE 9 is an enlarged (fifty power) cross-sectional photograph of apolyester fabric made from filament yarns prior to compacting.

FIGURE 10 is an enlarged (fifty power) cross-sectional photograph of apolyester fabric made from filament yarns subsequent to compacting bymeans of external forces.

FIGURE 11 is an enlarged (fifty power) cross-sectional photograph of apolyester/cotton fabric prior to compacting.

FIGURE 12 is an enlarged (fifty power) cross-sectional photograph of apolyester/cotton fabric subsequent to compacting by means of externalforces.

Turning to FIGURE 1 of the drawings, a roll of fabric 1 which may be afabric such as, for instance, a polyester fiber fabric is passed oversuitable guide roll member 2 into steamer member 3. The steamed fabricis then passed over the first of a plurality of compactor roll members4, the fabric being subjected to the compacting operation by passageover compactor roll members 4. It is also subjected to a simultaneoussetting operation, the setting operation being accomplished by means ofa bank of infrared lamp members 5 superimposed above the compactor rollmembers 4. It is preferred that the fabric be maintained in a moistenedcondition so as to increase the propensity of the fabric to compact, themoistening of the fabric being accomplished by means of the water vaporgenerated by heated water bath 6 positioned directly below compactorroll members 4. Maximum compacting is preferably obtained by immersionof the fabric into a water bath 7 by passage under an immersed compactorroll member 8 at a point substantially midway through the compactor rollseries. The water-wetted fabric is then subjected to the same type ofoperation as had been carried out prior to immersion in the water bath,that is to say the fabric is passed over additional compactor members 4simultaneous to being subjected to the action of infrared lamp members 5and moisture from heated water bath members 6, The now compacted fabricis passed over a singular noncontacting compactor roll member 9 which ispreferably of greater diameter than the preceding series of compactorroll members. The enlarged compactor roll member 9 serves to removewrinkles from the compacted fabric prior to subjecting the compactedfabric to the action of flat roll members. The wrinkle free compactedfabric is then passed beneath a lower squeeze roll 10 and then into nipformed by compacting an upper squeeze roll 11 with lower squeeze rollmember If). The fabric is then wound onto a suitable takeup roll 12which is driven by means of drive roll 13. Drive roll 13 as well 4 assqueeze roll member 11 is powered by a suitable driving means such as,for instance, an electric motor and pulley arrangement 14.

A better understanding of the compaction which takes place in the fabricby passage over compactor roll members 4 may be had from FIGURE 2 of thedrawings! wherein the reduction in width of fabric 21 is clearly notedin the passage of the fabric over compactor roll members 2.4. The endand side portions of water bath 27 have been cut away in order toclearly illustrate the passage of the fabric from the nip formed by twocontacting compactor roll members 24 around and underneath immersioncompactor roll member 28 and then again into the nip formed by twocontacting compactor roll members 24. For ease of illustration, thecompactor roll members 24 immediately above immersion compactor rollmember 28 and immediately preceding immersion compactor roll member 23have been cut away. As may be noted from an overall view of FIGURE 2,fabric 21 is being compacted from about 3% to about 5% in passing overeach of compactor roll members 24. Roll member 29, it should be noted,is positioned so as to expand compacted fabric 21, thereby removing anywrinkles which may have been produced in the compacting operation.

Fabrics which are suitable for compacting according to the processdescribed herein are any fabrics which are prepared with a reeded outconstruction, that is to say any fabrics which have a construction suchas will admit compacting along the direction of the filling yarns.Specific textile materials which may be employed in the construction ofsuch fabrics are any textile material which will lend themselves to asetting operation subsequent to or simultaneously with a compactingoperation. As previously mentioned, the setting operation may be any ofthe setting operations well known to the art such as, for instance, theuse of a reducing agent setting operation for yarns containingkeratinous fibers, the use of cross-linking agents in the setting ofcellulosic type yarn and the use of heat setting mediums forthermoplastic yarn, the selection of the particular setting medium beingemployed depending, of course, upon the type of fiber present to thegreatest degree in the yarn or the percentage of fibers of a particularnature coupled with the ability of such fibers to retain a permanentset.

The yarns employed in the fabrics suitable for compacting according tothe process described herein are both high and low twist yarns. Itshould be understood, however, that the process of this invention lendsitself to the preparation of stretch fabrics from fabrics containingyarns of lower twist multiple than may be employed in processes whichrequire internally generated compacting forces. When stretch fabrics areprepared by means of internally generated compacting forces such as inthe process described in US. Patent No. 3,077,655, worsted wool yarnshaving a twist multiple in excess of about 2.6 must be employed. Whenstretch fabrics are prepared according to the process set forth herein,however, worsted wool yarns having a twist multiple of less than about2.6 may be satisfactorily employed. correspondingly, low twist woolensystem yarns may also be satisfactorily employed, that is to say woolensystem yarns having a twist multiple of less than about 8 and preferablyfrom about 5 to about 8 may be employed. Twist multiple is a term commonto the textile industry and may be defined as turns per inch divided bythe square root of the yarn count.

The following specific examples for the preparation of the stretchfabrics of this invention are given for the purposes of illustration andshould not be considered as limiting the spirit or scope of thisinvention:

Example I An all wool fabric having 35 ends per inch and 29 picks perinch and having a warp and filling yarn count of 4.6 woolen run ispassed into a reducing agent bath comprising an aqueous solution ofsodium borohydride at a concentration of about 2% by weight. Thereducing agent treated fabric is then passed through a set of squeezerolls and then into a fourteen roll compactor roll appa ratus, theapparatus being of a type as previously described. The compacted fabricis then wound upon a decating roll and subjected to 2O minute agingoperation at a temperature of about 80 F. The fabric is then dried in aFleissner drier (relaxed drum drier) at 200 F. After drying the fabricis semi-decated with a cycle of steam breakthrough plus a ten secondsteaming followed by two minutes vacuum pumping. The wool fabric, set inits compacted configuration, is found to have a substantial degree ofstretch along the direction of the fill yarns. The stretch fabric isfound to have 46 ends per inch and 23 picks per inch.

Example II A 55% polyester/45% worsted wool fabric having 49 ends perinch and 43 picks per inch and a worsted warp yarn count of /1 and aworsted filling yarn count of 20/1 is fed into a sixteen roll compactorroll apparatus, the apparatus being of the type previously described.The apparatus is allowed to force the fabric into about 40% of itsoriginal width. Simultaneous to the compacting operation, thepolyester/worsted wool fabric is subjected to a heat treatment attemperatures approaching a suitable thermal transition point of thepolyester fibers. The compacted fabric upon emerging from the compactorroll apparatus is found to have 40% stretch when subjected to a load oftwo pounds per inch of fabric sample width and an unrecovered stretch of3.9%, the unrecovered stretch being reported on the basis of percentageof the orginal length after being held five minutes at extension andallowed to recover five minutes after unloading.

Example III A 100% cotton fabric having 76 ends per inch and 70 picksper inch is fed into a nineteen roll compactor roll apparatussubstantially as previously described. The fabric upon emerging from thecompactor roll apparatus is found to have been compacted about of itsoriginal width. The cotton fabric is then set in its compactedconfiguration by treatment with a dihydroxy dimethylol ethylene ureacross-linking agent. The final product is found to have 35 stretch undera load of two pounds per inch of sample width and to have a 5.6%unrecovered stretch, the unrecovered stretch being reported as percentof original length after being held five minutes at 30% extension andallowed to recover five minutes after unloading.

Example IV A polyester continuous filament yarn having 144 ends per inchand 100 picks per inch and having a denier yarn count in both the warpand filling directions is subjected to the same processing operation asset forth in Example II. The finished product is found to have 227 endsper inch and 99 picks per inch and to have a 34% stretch at a load oftwo pounds per inch of sample width with 8.0% unrecovered stretch, theunrecovered stretch being reported as percent of original length afterfive minutes at 30% extension and allowed to recover five minutes afterunloading.

Example V A 65% polyester/35% cotton fabric having 92 ends per inch and76 picks per inch and a yarn count (cotton system) of /1 in both thewarp and filling direction is processed according to the procedure setforth in Example II. The finished product is found to have 121 ends perinch, 74 picks per inch and to have a stretch of 35% under a load of twopounds per inch of sample width with an unrecovered stretch of 5.4%. Theunrecovered stretch is reported as percent of original length afterbeing held five minutes at 30% extension and allowed to recover fiveminutes after unloading.

Example VI A fabric having a fiber content of 65% polyester and 35%cotton and a construction of 87 ends per inch and 67 picks per inch isprocessed according to the procedure set forth in Example II, thecompaction produced by the compactor roll apparatus being about a 42%reduction of the original width of the fabric. The fabric having a yarncount in the cotton system of 40/ l in both the warp and fillingdirections is a fabric having 113 ends per inch, 62 picks per inch and astretch of 42% under a load of two pounds per inch of sample width, theunrecovered stretch being 5.8%. The unrecovered stretch is reported aspercent of original length after being held five minutes at 30%extension and allowed to recover five minutes after unloading.

Example VII A fabric having a fiber content of 65% polyester/35% rayonand having a fabric construction of 64 ends per inch and 60 picks perinch with a yarn count on the cotton system of 20/1 in both the warp andfilling direction is processed according to the procedure set forth inExample II. The final product is found to be a fabric having 90 ends perinch, 56 picks per inch and a stretch of 30% a load at two pounds perinch of sample width. The unrecovered stretch is found to be 5.5%,unrecovered stretch being reported as percent of original length afterbeing held five minutes at 30% extension and allowed to recover fiveminutes after unloading.

The determination of elasticity in the finished product as reported inthe foregoing examples was determined by cutting test specimens 2 inchesby 24 inches with the longer length being parallel to the stretchdirection. The upper end of the test specimen is then secured to a clampmember while the lower end of the test specimen is subjected to a loadof four pounds (two pounds per inch). The specimen is then exercised bycycling three times between a zero load and a two pound load atapproximately five seconds per cycle. The increase in length is thenrecorded within 30 seconds after the completion of the fourth loadingcycle. The increase in length over the initial length multiplied by isthen recorded as the percent stretch.

The extent to which a fabric has been compacted and correspondinglygiven stretch characteristics is readily discernible from a review ofFIGURES 3 through 12 which are enlarged photographs of fabrics andfabric cross sections prior to compacting and subsequent to compactingoperations. The cross sections in each of FIGURES 3 through 12 are crosssections made by cutting through the warp yarns. The increase in bothfrequency and amplitude of the filling yarns may be seen in each set offabric cross sections subsequent to compacting. It is important to notethat the finished stretch fabric prepared according to the process ofthis invention may be a fabric having low twist yarns, the low twistyarns, of course, having greater bulk and resulting in a fabric having asuperior hand than fabrics prepared from the high twist yarns which arenecessary in the preparation of fabrics compacted by internal forces.While the stretch fabrics of this invention may be prepared from eitherhigh or low twist yarns, it is an important feature of the presentinvention that stretch fabrics may be prepared from yarns havinginsulficient twist to produce internal compacting forces.

Having thus described the invention, what is claimed is:

1. A continuous process to impart stretch characteristics to a wovenfabric having an open weave comprising: supplying said open weave fabricto a compacting surface, compacting said fabric in the fill direction onsaid comr pacting surface, maintaining said fabric in compactedcondition while supplying said fabric to a further compacting surface,compacting said fabric further in the fill direction, repeating thecompacting of said fabric in the fill direction on further compactingsurfaces While maintaining the fabric in its compacted conditions at alltimes and setting the fabric in its compacted configuration.

2.. The process of claim 1 wherein said fabric is compacted from about1% to 10% in width on each compacting surface.

3. The process of claim 2 wherein said fabric is compacted in the filldirection greater than 25%.

4-. The process of claim 1 wherein the fabric is set in the compactedconfiguration simultaneously to compaction on said compaction surfaces.

5. A continuous process to impart stretch characteristics to a wovenfabric having an open weave comprising: supplying said open Weave fabricto the long side of an arcuate member, moving said fabric from the longside of said arcuate member to the short side of said arcuate member tocompact the width of the fabric, maintaining 6. The process of claim SWherein said fabric is compacted from about 1% to 10% in width on eacharcuate member.

7. The process of claim 6 wherein said fabric is compacted in the filldirection greater than 25%.

8. The process of claim 5 wherein the fabric is set in the compactedconfiguration simultaneously to compaction on said arcuate member.

References Cited UNITED STATES PATENTS 1,988,376 1/1935 Dcsmet 26-186-2,849,781 9/1958 Rosen 26-186 3,100,925 8/1963 Messinger 26-1861,660,224 2/1928 Farrell 26-63 1,814,652 7/1931 Weiss 26-63 2,021,97511/1935 Wrigley et al. 26-186 2,535,734 12/1950 Grettve. 2,574,20011/1951 Teague 26-186 X 2,626,422 1/1953 Lammertse 26-63 X 2,905,9999/1959 Parker et a1 26-54 X 2,979,131 4/1961 Bontov.

FOREIGN PATENTS 43,197 5/1938 Netherlands.

ROBERT R. MACKEY, Primary Examiner.

1. A CONTINUOUS PROCESS TO IMPART STRETCH CHARACTERISTICS TO A WOVENFABRIC HAVING AN OPEN WEAVE COMPRISING: SUPPLYING SAID OPEN WEAVE FABRICTO A COMPACTING SURFACE, COMPACTING SAID FABRIC IN THE FILL DIRECTION ONSAID COMPACTING SURFACE, MAINTAINING SAID FABRIC IN COMPACTED CONDITIONWHILE SUPPLYING SAID FABRIC TO A FURTHER COMPACTING SURFACE, COMPACTINGSAID FABRIC FURTHER IN THE